System and method for medical imaging with robust mode switching via serial channel

ABSTRACT

In one embodiment of the invention, there is an ultrasound processing system that communicates images over a single asynchronous serial channel according to a scheme that does not require an isochronous serial channel and that switches among ultrasound imaging modes robustly. For example, the system is configured to packetize ultrasound image data of at least one ultrasound imaging mode into a stream of data frames and to convey the stream of data frames via the asynchronous channel. Each data frame includes indication of the ultrasound imaging mode and includes ultrasound-imaging-mode-specific imaging parameters. Other embodiments exist.

RELATED APPLICATION(S)

The present patent application is related to and claims the benefit ofpriority from commonly-owned U.S. Provisional Patent Application No.60/623,796, filed on Oct. 30, 2004, entitled “Medical Imaging SystemData Transport”, which is hereby incorporated by reference in itsentirety for all purposes.

TECHNICAL FIELD

The present invention relates to medical imaging. The present inventionis especially relevant to medical ultrasound imaging.

BACKGROUND

Medical imaging systems are used to obtain images of a patient's body.For example, medical imaging systems based on ultrasound technologytransmit high frequency sound waves into a patient's body and thenreceive and process returning echoes to obtain two or three dimensionalimages, for example, time-varying images. Medical imaging systems ingeneral and ultrasound imaging systems in particular are known in theart.

Various types, or modalities, of imaging are known in the art. Forexample, there are algorithms for producing B-mode images (brightness),C-mode images (color), D-mode images (Doppler), M-mode images (motion),combination modes (e.g., B+C or B+D or B+C+D), or the like. During use,an imaging system may be switched from one mode to another at the whimof the operator (e.g., a physician or a technician).

FIG. 1 schematically illustrates a conventional ultrasound imagingsystem 100. The conventional system 100 includes: a front-end portion110 a that includes a scanner and a processor, and a back-end portion112 a that includes a processor. The front-end portion 110 a includes,or works with, an ultrasound probe 114 a. The back-end portion 112 aincludes, or works with, a display 116 b. The conventional system 100uses, for example, a serial bus 120 (for example, USB (Universal SerialBus) 2.0 or IEEE1394 FireWire™) for ultrasound image data transferbetween the front-end portion 110 a and the back-end portion 112 a. Theserial bus 120 utilizes an Isochronous channel 122 for transferringimage packets and an Asynchronous channel 124 for transferring Commandand Control parameters. Command and Control parameters include, forexample, instructions to switch into particular modes, as well asmode-specific parameters (e.g., frame size, number of zones, timesequence information, and the like) including parameters that define howto interpret the image packets of the Asynchronous channel. TheIsochronous channel 122 supports a real-time, high-throughput image-datatransfer, in which a data packet can be dropped if the throughput of thechannel becomes problematic. There is no guarantee that any particularimage packet will be transferred, but the image frames that aretransferred will always be in real time. In contrast, the Asynchronouschannel 124 has a lower priority in sharing the channel bandwidth andsupports packet transfer without any guarantee of real-time delivery,for low-throughput command and parameter communication.

FIG. 2 schematically illustrates another conventional ultrasound imagingsystem 150. The conventional system 150 includes: a front-end portion110 b that includes a scanner and a processor, and a back-end portion112 b that includes a processor. The front-end portion 110 b includes,or works with, an ultrasound probe 114 b. The back-end portion 112 bincludes, or works with, a display 116 b. The conventional system 150uses a PCI bus 160 to transfer ultrasound image data and controlparameters between the front-end portion 110 b and the back-end portion112 b. The PCI bus is a parallel bus inside the PC motherboard thatsupports, e.g., a 132 Mb/s throughput rate with a critical timingrequirement.

SUMMARY OF THE INVENTION

In an ultrasound medical imaging system, there is a unique requirementin which several modes (for instance, B, Color, Doppler, etc.) need tobe switched in real time. Such switching creates a synchronizationproblem in the mode transition. In general, in the serial-bus-interfaceconventional system of FIG. 1, the image data in the Isochronous channel122 has difficulty in maintaining synchronization with thecommand/parameter coming through the Asynchronous channel 124, and willcause the image to be out of sync or even crash the ultrasound system.In general, in the PCI-interface conventional system, the implementerneeds to design a PCI add-on card in the PC motherboard and needs tomaintain very critical timing requirements for every bit, using a largenumber of wires in parallel.

What is needed are an improved method and system for a medical imagingsystem that includes robust data transport. Embodiments of the presentinvention include a method and a system for data transport in a medicalimaging system, for example, an ultrasound medical imaging system.Embodiments of the present invention also include a medical imagingmethod and a medical imaging system that include method and system forthe data transport.

According to one embodiment of the present invention, there is a systemfor ultrasound medical imaging. The system includes a first and a secondultrasound information processing device. The first ultrasoundinformation processing device is configured to packetize ultrasoundimage data of at least one ultrasound imaging mode into a stream of dataframes and to convey the stream of data frames via a serialcommunication channel. Each of multiple data frames over a duration ofthe stream of data frames includes indication of the ultrasound imagingmode and includes ultrasound-imaging-mode-specific imaging parameters.The imaging parameters included by the each of multiple data frames aredescriptive of structure or time sequence of image data within the eachof multiple data frames. The second ultrasound information processingdevice is configured to receive the stream of data frames via the serialcommunication channel, and to recognize ultrasound imaging mode ofreceived image data and structure of received image data fromindications within a data frame that contained the received image data.

According to one embodiment of the present invention, there is a methodfor ultrasound medical imaging. The method includes the acts of:transmitting ultrasound acoustic waves into the body of a patient;receiving and processing, according to one or more ultrasound imagingmodes, echoes reflected from structures within the patient's body toform ultrasound image data; packaging ultrasound image data of at leastone ultrasound imaging mode into a stream of data frames, each ofmultiple data frames over a duration of the stream of data framesincluding indication of the ultrasound imaging mode and includingultrasound-imaging-mode-specific imaging parameters, the imagingparameters within the each of multiple data frames being descriptive ofstructure or time sequence of image data within the each of multipledata frames; conveying the stream of data frames via a serialcommunication channel; receiving the stream of data frames via theserial communication channel; recognizing ultrasound imaging mode ofreceived image data and structure of received image data fromindications within a data frame that contained the received image data;processing the received image data, based on recognized mode andstructure of the received image data; and displaying the processedreceived image data.

According to one embodiment of the present invention, there is acomputer memory product. The computer memory product includes: at leastone computer readable storage medium; first computer code stored on theat least one computer readable storage medium; and second computer codestored on the at least one computer readable storage medium. The firstcomputer code includes instruction to at least a first computerprocessor to: package ultrasound image data of at least one ultrasoundimaging mode into a stream of data frames, each of multiple data framesover a duration of the stream of data frames including indication of theultrasound imaging mode and including ultrasound-imaging-mode-specificimaging parameters, the imaging parameters within the each of multipledata frames being descriptive of structure or time sequence of imagedata within the each of multiple data frames; and convey the stream ofdata frames via a serial communication channel. The second computer codeincludes instruction to at least a second computer processor to: receivethe stream of data frames via the serial communication channel;recognize ultrasound imaging mode of received image data and structureof received image data from indications within a data frame thatcontained the received image data; and process the received image data,based on recognized mode and structure of the received image data, tofacilitate display of the received image data.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more extensively describe some embodiment(s) of the presentinvention, reference is made to the accompanying drawings. Thesedrawings are not to be considered limitations in the scope of theinvention, but are merely illustrative.

FIG. 1 schematically illustrates a conventional ultrasound imagingsystem.

FIG. 2 schematically illustrates another conventional ultrasound imagingsystem.

FIG. 3 schematically illustrates an ultrasound imaging system accordingto an embodiment of the present invention.

FIGS. 4A-4D schematically illustrate data frame structure for dataframes used during B-mode imaging, B+C-mode imaging, B+D-mode imagingand B+M-mode imaging.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Medical imaging systems are known. For example, ultrasound imaging isdiscussed in U.S. Pat. Nos. 6,248,071 and 6,547,730, which are herebyincorporated by reference in their entirety for all purposes.

According to some embodiments of the present invention, there is a datatransport for a real-time medical imaging system (e.g., ultrasound) thatconsolidates medical imaging data and control parameters into a singlecommunication channel in a serial bus interface in a robust manner.

FIG. 3 schematically illustrates an ultrasound imaging system 300according to an embodiment of the present invention. The system 300includes: a front-end portion 310 that includes a scanner and aprocessor, and a back-end portion 312 that includes a processor. Thefront-end portion 310 includes, or works with, an ultrasound probe 114c. The back-end portion 312 includes, or works with, a display 116 c.The componentry and imaging algorithms of the front-end portion 310 andthe back-end portion 312 can be according to any known type. However,the front-end portion 310 and the back-end portion 312 includeinformation processing devices that are configured to communicateinformation in accordance with the present document.

The system 300 is configured to use, for example, a serial bus (forexample, USB 2.0 or IEEE1394 FireWire™) for ultrasound image datatransfer between the front-end portion 310 and the back-end portion 312.The system 300 is configured to be able to utilize a channel 320 of theserial bus, during use of the system 300. For example, the channel 320is preferably a non-Isochronous channel, and the system 300 ispreferably configured to be able to utilize the non-Isochronous channel(320) of the serial bus, during use of the system 300, without requiringutilization of any Isochronous channel that the serial bus might ormight not be configured to provide. For example, the non-Isochronouschannel (320) may be an Asynchronous channel, and the Asynchronouschannel is preferably used to transfer both image packets and Commandand Control parameters. Preferably, the Asynchronous channel is one thatincludes error detection or error control capability to help enable areceiver of communications to ensure guaranteed correct and completecommunication.

Command and Control parameters include, for example, instructions toswitch into particular modes, as well as mode-specific parameters (e.g.,frame size, number of zones, and the like) that define how to interpretthe image packets of the Asynchronous channel. For example, the system300 is configured to use the Asynchronous channel to transfer both imagepackets and Command and Control parameters, according to a data packetframe structure.

According to some embodiments of the present invention, the image datais pre-processed and packetized (e.g., including data compression) intoa small volume, and a header section with the control parameter can beattached in the image packet, and together the image and controlinformation is sent through the Asynchronous channel. The image datawill be always in sync with the control parameters associated with thatspecific image packet during the transition of the scan mode changes.The imaging packet won't be out of sync with the control parametersduring the scan mode changes. Further, the processing burden on thecontroller (e.g., on a controller running a Linux operating systemkernel, or any other competent operating system) is lessened. Forexample, the device driver (e.g., a Linux device driver) does not haveto maintain two ports, one for Isochronous and the other forAsynchronous. For another example, the controller does not have to useelaborate (and imperfect) schemes to try to synchronize imaging packagesand their corresponding control information.

With pre-processing and image data packetization, the image data size isfirst significantly reduced, and both image data and parameters arefitted into a low throughput rate Asynchronous channel. The system doesnot have to rely on both an Isochronous and an Asynchronous channel forthe ultrasound system image transfer. It can maintain a goodsynchronization on the image data packet and control parameters. The netchannel bandwidth requirement can be reduced down to 200 Mb/s over theserial bus interface such as USB or IEEE1394, for many typical imagingsizes and image rates. Depending on the available bandwidth,compression, of course, may not be necessary. If compression is used,any type of data compression may be used. For example, compression basedon the cosine transform (which is commonly used in the JPEG imagecompression scheme), may be employed.

Accordingly, simply the Asynchronous port is used to transfer both imageand control data in between ultrasound front end and back end units. NoIsochronous or PCI parallel bus are required. In an ultrasound system,the mode (e.g. B, Color, Doppler, M, etc.) changes in real time. It isconventionally extremely difficult to keep the parameter/command in syncwith the ultrasound image data, and the designer uses an Isochronouschannel for the image transfer in a serial communication bus or uses aparallel PCI bus for image transfer. In some of our embodiments,pre-processing and packaging are used (e.g., including datacompression), and both the image data and the control parametersassociated with the data packet are consolidated into one packet that isfitted into a low throughput rate Asynchronous channel and also preventthe image from being out of sync with the parameter and crashing thesystem. No separate Isochronous channel is required.

In one example implementation, preprocessing includes reducing front-endsampling data (e.g., 8000 per vector) to display pixel density (e.g. 400per vector and 128 vector per frame) to send only the data which arevisible on the display).

As has been discussed, an isochronous channel is preferably not requiredand not used. In one embodiment, even if an isochronous channel is forsome reason nevertheless used, then still a non-Isochronous channel,e.g., an Asynchronous channel is used to transfer at least half of allultrasound images being transferred during a typical user session.

FIGS. 4A, 4B, 4C and 4D schematically show example data frame structuresaccording to an embodiment of the present invention. FIG. 4Aschematically shows data frame structure for a data frame 400 that isused during B-mode imaging. The data frame 400 includes: a B-mode header410 a, data 412 a that includes B-mode image data and B-mode parameters,and a frame tailer 414 a. FIG. 4B schematically shows data framestructure for a data frame 420 that is used during B+C-mode imaging. Thedata frame 420 includes: a B-mode header 410 b, data 412 b that includesB-mode image data and B-mode parameters, a C-mode-specific header 430,data 432 that includes C-mode image data and C-mode parameters, and aframe tailer 412 b. FIG. 4C schematically shows data frame structure fora data frame 440 that is used during B+D-mode imaging. The data frame440 includes: a B-mode header 410 c, data 412 c that includes B-modeimage data and B-mode parameters, a D-mode-specific header 450, data 452that includes D-mode image data and D-mode parameters, and a frametailer 412 c. FIG. 4D schematically shows data frame structure for adata frame 460 that is used during B+M-mode imaging. The data frame 460includes: a B-mode header 410 d, data 412 d that includes B-mode imagedata and B-mode parameters, an M-mode header 450, data 452 that includesM-mode image data and M-mode parameters, and a frame tailer 412 d.

As can be seen, each block of image data (e.g., within data 412 a-d,432, 452 or 472) are accompanied very nearby (e.g., within a same dataframe) by corresponding command and control information that indicatesto the recipient of the block how to interpret the block (e.g., whatimaging mode the block is, number of parameters, the parameters, and thelike). For example, one block of B-mode imaging data may correspond to asingle two-dimensional image. In a combination imaging mode (e.g., B+C,B+D, B+M, B+C+D, etc.), successive data frames would implement aninterleaving of the data of the different imaging modes being combined,e.g., B-C-B-C-B-C- . . . for B+C mode (see. FIG. 4B) or (not shown)B-C-D-B-C-D-B-C-D- . . . for B+C+D mode.

The recipient (e.g., back-end portion 312 in FIG. 3) of data frames ofimaging data according to the scheme of FIG. 3 can process the imagingdata according to the command and control information that appears in aheader and in parameters of the same data frame of the imaging data. Inthis way, at the recipient, the state of the system, which statereflects the sum history of command and control information up to aparticular time, maintains synchronization with the actual image datathat corresponds to the state of the system.

As is clear from the above, an ultrasound system according to anembodiment of the present invention can be a conventional ultrasoundsystem that is modified to communicate information in accordance withthe present document. Thus, the processors in the front-end and back-endportions of such an ultrasound system are provided with software storedin computer memory media that instruct those processors to execute someof the methodologies described in the present document. An embodiment ofthe present invention is a computer memory product that includes any ofsuch instructions. An embodiment of the present invention is either thefront-end portion by itself, or parts thereof, or the back-end portionby itself, or parts thereof.

For example, in an embodiment, a front-end processor is to be instructedto packetize image data and parameters of a particular imaging mode intoa data frame that includes a header, the header indicating at least theimaging mode. In a usage session, even when the operator does not changethe imaging mode being used, multiple data frames (e.g., successive dataframes) being transmitted will nevertheless each indicate the imagingmode, and will still each include imaging-mode-specific imageparameters. In some sense, such indicated and included information inthe multiple data frames can be considered redundant. If a combinationmode is being implemented, then the blocks of imaging data for thedifferent modes being combined are interleaved. For example, one dataframe may include blocks of imaging data for all the different imagingmodes being combined. That one data frame includes header and parameterinformation for the blocks of imaging data within that data frame. Forexample, each block within that one data frame may have its own header(as shown in FIGS. 4B, 4C and 4D).

The description and the drawings of the present document describeexamples of embodiment(s) of the present invention and also describesome exemplary optional feature(s) and/or alternative embodiment(s). Itwill be understood that the embodiments described are for the purpose ofillustration and are not intended to limit the invention specifically tothose embodiments. For example, ultrasound embodiments were discussed,but the invention may also be embodied for any other type of medicalimaging system. Rather, the invention is intended to cover all that isincluded within the spirit and scope of the invention, includingalternatives, variations, modifications, equivalents, and the like.

1. A system for ultrasound medical imaging, the system comprising: afirst ultrasound information processing device configured to packetizeultrasound image data into a stream of data frames and to convey saidstream of data frames and control parameters via a serial communicationchannel, wherein each of multiple data frames conveyed over a durationof said stream of data frames includes an indication of an ultrasoundimaging mode and includes ultrasound-imaging-mode-specific imagingparameters within each of multiple data frames that are descriptive ofstructure of a data frame, wherein the structure of each data framecomprises a header and a body, the image data and control parametersarranged to remain in sync during scan mode changes, the image datastored in the body, the control parameter stored in the header; and asecond ultrasound information processing device configured to receivesaid stream of data frames and control parameters via said serialcommunication channel, and to recognize the ultrasound imaging mode ofreceived image data from the indication.
 2. A system according to claim1, wherein said serial communication channel comprises an asynchronouschannel, and said stream of data frames is communicated via saidasynchronous channel.
 3. A system according to claim 2, wherein saidasynchronous channel is configured to include error control capability.4. A system according to claim 1, wherein an isochronous serialcommunication channel is not required for communicating ultrasound imagedata from said first ultrasound information processing device to saidsecond ultrasound information processing device.
 5. A system accordingto claim 1, configured wherein said serial communication channelcomprises a non-isochronous channel, and at least half of all ultrasoundimage data conveyed from said first ultrasound information processingdevice to said second ultrasound information processing device during auser session is communicated via said non-isochronous channel.
 6. Asystem according to claim 1, wherein said first ultrasound informationprocessing device is configured wherein said duration of said stream ofdata frames is one over which a human operator receiving the stream ofdata frames has not changed at least one ultrasound imaging mode.
 7. Asystem according to claim 1, wherein said first ultrasound informationprocessing device is configured, when brightness mode, hereinafterreferred to as B-mode, is desired by the human operator, to produce astream of data frames that each have a first header that indicatesB-mode, a body that includes B-mode image data and B-mode parameters,and a frame tailer; and wherein said first ultrasound informationprocessing device is configured, when brightness-and-color mode,hereinafter referred to as B+C-mode, is desired by the human operator,to produce a stream of data frames that each have a second header thatindicates B-mode, a body that includes B-mode image data and B-modeparameters, a third header that indicates color mode, hereinafterreferred to as C-mode, a body that includes C-mode image data and C-modeparameters, and a frame tailer.
 8. A system according to claim 7,wherein said first ultrasound information processing device isconfigured, when brightness-and-doppler mode, hereinafter referred to asB+D-mode, is desired by the human operator, to produce a stream of dataframes that each have a first header that indicates B-mode, a body thatincludes B-mode image data and B-mode parameters, a second header thatindicates doppler mode, hereinafter referred to as D-mode, a body thatincludes D-mode image data and D-mode parameters, and a frame tailer. 9.A method for ultrasound medical imaging, the method comprising:transmitting ultrasound acoustic waves into a body of a patient;receiving and processing, according to one or more ultrasound imagingmodes, echoes reflected from structures within the patient's body toform ultrasound image data; packaging ultrasound image data formed usingat least one ultrasound imaging mode into a stream of data frames, eachof multiple data frames over a duration of said stream of data framesincluding an indication of the ultrasound imaging mode, controlparameters and ultrasound-imaging-mode-specific imaging parameters, theimaging parameters within the each of multiple data frames beingdescriptive of structure of a data frame within each of multiple dataframes, wherein the structure of each data frame comprises a header anda body, the image data and control parameters arranged to remain in syncduring scan mode changes, the image data stored in the body, the controlparameters stored in the header, wherein the control parameters comprisean instruction for switching modes; conveying said stream of data framesvia a serial communication channel; receiving said stream of data framesvia said serial communication channel; recognizing ultrasound imagingmode of received image data from the indication within a data frame;processing the received image data, based on recognized mode, structureof each received data frame and the control parameters; and displayingthe processed received image data.
 10. A method according to claim 9,wherein said serial communication channel comprises an asynchronouschannel, and said conveying step comprises conveying said stream of dataframes via said asynchronous channel.
 11. A method according to claim10, wherein said asynchronous channel is configured with error controlcapability.
 12. A method according to claim 9, wherein an isochronousserial communication channel is not required for said conveying,receiving, or recognizing steps.
 13. A method according to claim 9,wherein said serial communication channel comprises an asynchronouschannel, and said conveying step comprises conveying via saidnon-isochronous channel at least half of all image data to be conveyedfrom said first ultrasound information processing device to said secondultrasound information processing device during a user session.
 14. Amethod according to claim 9, wherein said packaging step is as describedeven when said duration of said stream of data frames is one over whicha human operator receiving the stream of data frames has not changed theat least one ultrasound imaging mode.
 15. A method according to claim 9,wherein said packaging step comprises, when brightness mode, hereinafterreferred to as B-mode, is desired by the human operator, producing astream of data frames that each have a first header that indicatesB-mode, a body that includes B-mode image data and B-mode parameters,and a frame tailer; and wherein said packaging step comprises, whenbrightness-and-color mode, hereinafter referred to as B+C-mode, isdesired by the human operator, producing a stream of data frames thateach have a second header that indicates B-mode, a body that includesB-mode image data and B-mode parameters, a third header that indicatescolor mode, hereinafter referred to as C-mode, a body that includesC-mode image data and C-mode parameters, and a frame tailer.
 16. Amethod according to claim 15, wherein said packaging step comprises,when brightness-and-doppler mode, hereinafter referred to as B+D-mode,is desired by the human operator, producing a stream of data frames thateach have a first header that indicates B-mode, a body that includesB-mode image data and B-mode parameters, a second header that indicatesdoppler mode, hereinafter referred to as D-mode, a body that includesD-mode image data and D-mode parameters, and a frame tailer.
 17. Acomputer memory product, comprising: at least one computer readablestorage medium; first computer code stored on said at least one computerreadable storage medium, the first computer code including instructionto at least a first computer processor to: package ultrasound image datainto a stream of data frames, each of multiple data frames over aduration of said stream of data frames including an indication of anultrasound imaging mode, control parameters andultrasound-imaging-mode-specific imaging parameters, the imagingparameters within said each of multiple data frames being descriptive ofstructure of a data frame within the said each of multiple data frames,wherein the structure of each data frame comprises a header and a body,the image data and control parameters arranged to remain in sync duringscan mode changes, the image data stored in the body, the controlparameter stored in the header; and convey said stream of data framesvia a serial communication channel; and second computer code stored onsaid at least one computer readable storage medium, the second computercode including instruction to at least a second computer processor to:receive said stream of data frames via said serial communicationchannel; recognize the ultrasound imaging mode of received image datafrom the indication within a data frame and the structure of eachreceived data frame; and process the received image data, based onrecognized mode and structure of each received data frame, to facilitatedisplay of the received image data.
 18. A computer memory productaccording to claim 17, wherein said instruction to convey comprisesinstruction to convey said stream of data frames via an asynchronouschannel.
 19. A computer memory product according to claim 18, whereinsaid instruction to convey does not require an isochronous serialcommunication channel.
 20. A computer memory product according to claim17, wherein said instruction to at least a first computer processor isconfigured for said instruction to package to be executed even over aninstance of said duration of said stream of data frames over whichdesired ultrasound imaging mode remains unchanged by a human operatorwho is viewing displayable image data.